2 R.I. beaches report relief from isopods after wind change

At least two major beaches in Rhode Island were reporting relief Thursday from a statewide infestation of little critters nicknamed “sea roaches” that had some swimmers too disgusted to stay in the water...

At least two major beaches in Rhode Island were reporting relief Thursday from a statewide infestation of little critters nicknamed “sea roaches” that had some swimmers too disgusted to stay in the water earlier in the week.

Their numbers at Middletown’s Sachuest Beach, which had been described in the “millions” in previous days, were way down, said assistant beach manager Joseph Benedetti. Similar reports were received from Scarborough State Beach.

On Wednesday, state officials said the quarter-inch to half-inch organisms were being reported from Sachuest to Westerly, while one reader on Martha’s Vineyard said they were legion there as well. The officials identified them as crustacean isopods.

“The three little ones I scooped up are idotea baltica,” said Sheldon Pratt, a marine research associate at the University of Rhode Island, who was curious about the news reports and decided to investigate at the small beach at the Bay campus. “Some people call them saltwater pill bugs, which is actually accurate because the pill bug you find under a log is a crustacean.”

Jason McNamee, a marine biologist with the Department of Environmental Management, said he has seen them for years while conducting local fish-population surveys. They are typically found around seaweed.

“They’re not hurting anything,” he said. “They’re just gross.”

Marc Archambault would beg to differ. On Thursday, he was visiting Gooseberry Beach in Newport from Maine and said he and others in the water kept getting isopods on them and feeling small pricks. He didn’t believe reports that they don’t bite.

Pratt said the isopods aren’t biting, but instead have probably lost their perch on some seaweed and are grabbing hold of whatever they drift onto.

“They have good strong little claws,” he said.

While isopods are not uncommon in Rhode Island waters, the concentration of them in recent days has been rather remarkable, McNamee and other experts agreed. Possible factors include water temperatures hovering in the mid-70s, light breezes and tame surf. It’s possible that the conditions led to a spike in the isopod population or that they have not been disbursed by wind and waves as much as usual.

“I would say it’s probably a little bit of both,” said Erik Sotka, associate professor of biology at the College of Charleston in South Carolina. After being alerted to the infestation in Rhode Island, he said, “It looks like the beasts we’ve been playing with for a while. We’ve been comparing populations of that animal up and down the coast. It’s a very wide-ranging species from Chesapeake up into New England.”

Bathers who can’t stand seaweed shouldn’t be too quick to hate the crustaceans, he said. After all, they gorge on algae — thinning it out and preventing it from dying, sinking to the bottom and fouling the water. Fishermen should appreciate isopods too, he said.

“This is a vacuum cleaner of algal spores and small algae and large algae, too,” Sotka said. “It converts all of that seaweed into fish food because fish eat these [crustaceans] quite readily.”

Sotka, whose research team actually visited Rhode Island once to collect samples of local isopods, speculates that climate change and warming oceans could possibly mean more isopods in bathers’ future.

“These crustaceans can respond very quickly to warming waters,” he said. “It’s likely we are going to see their populations explode more frequently.”